1. Field of the Invention
The present invention relates generally to horizontal bandsaw machines having a flexible endless bandsaw blade trained around a plurality of wheels or pulleys to perform cutting operations and, more particularly, pertains to apparatus for detecting deviations of the bandsaw blade from the desired line of cut in horizontal bandsaw machines.
2. Descripton of the Prior Art
As is well known, horizontal bandsaw machines comprise a base on which workpieces to be cut are placed and held and a saw head assembly in which a flexible endless bandsaw blade is trained around a pair of wheels or pulleys, one of which is driven. Usually, the bandsaw blade is slidably held and guided by a pair of guide means at the cutting zone where cutting operations are to be made. The saw head assembly is so arranged as to be lowered and raised toward and away from the base by a suitable means such as a hydraulic motor, with movement of the head assembly either being pivotal around a hinge pin or vertical along appropriate vertical guide means. Thus, in cutting operations, the saw head assembly is lowered toward the base from its raised position so as to enable the driven bandsaw blade to cut the workpieces which have been placed on the base. Also, in automatic horizontal bandsaw machines, there are provided arrangements for automatically raising and lowering the saw head assembly and automatically feeding the workpieces into the cutting zone after completion of each cutting cycle.
One difficulty which has been encountered with conventional horizontal bandsaw machines of the above described type is that because the bandsaw blade is flexible, it will often deviate or vary laterally out from the desired line of cut to be made on the workpiece, even though it is guided by the guide means at the cutting zone. Particularly, the bandsaw blade has a tendency to laterally deviate as it becomes worn and especially when cutting difficult-to-cut materials such as stainless steels, heat-resisting steels and anticorrosion alloys. Such deviations of the bandsaw blade adversely affect cutting accuracy which in extreme cases necessitates scrapping of the workpiece. Since the deviations of the bandsaw blade cannot be readily noticed during cutting operations, it has often occurred that a number of scrap pieces are automatically and continuously produced from high-priced materials in automatic horizontal bandsaw machines. For these reasons, there has been a great need, heretofore unfullfilled, for a means to immediately and automatically detect the deviations of the bandsaw blade, especially in automatic horizontal bandsaw machines, without requiring constant attention by the saw operator.